The at sign, @, is normally read aloud as "at"; it is also commonly called the at symbol or commercial at. It is used as an accounting and invoice abbreviation meaning "at a rate of" (e.g. 7 widgets @ £2 per widget = £14),[1] but it is now most commonly used in email addresses and social media platform "handles".

The absence of a single English word for the symbol has prompted some writers to use the French arobase[2] or Spanish and Portuguese arroba, or to coin new words such as ampersat,[3]asperand,[4] and strudel,[5] but none of these has achieved wide use. The term alphasand is sometimes used, especially in East Asia.[citation needed]

Although not included on the keyboard of the earliest commercially successful typewriters, it was on at least one 1889 model[6] and the very successful Underwood models from the "Underwood No. 5" in 1900 onward. It started to be used in email addresses in the 1970s, and is now universally included on computer keyboards.

In unicode, the at sign is encoded as U+0040@COMMERCIAL AT (HTML &#64;), or &commat; in HTML5.[7]

@ used to signify French "à" ("at") from a 1674 protocol from a Swedish court (Arboga rådhusrätt och magistrat)

The earliest yet discovered symbol in this shape is found in a Bulgarian translation of a Greek chronicle written by Constantinos Manasses in 1345. Held today in the Vatican Apostolic Library, it features the @ symbol in place of the capital letter alpha "Α" in the word Amen. Why it was used in this context is still a mystery.

In terms of the commercial character of the at sign, there are several theories pending verification.

One theory is that the symbol developed as a Venetian mercantile shorthand symbol of "each at," the symbol resembling a lowercase "a" inside a lowercase "e," to distinguish it from the different "at" (symbolized by the mere letter "a") or "per."

Another theory is that medieval monks abbreviated the Latin word ad (at, toward, by, about) next to a numeral. One reason for the abbreviation saving space and ink. Since thousands of pages of biblical manuscripts were copied onto expensive papyrus or hides, and the words at, toward, by and about repeated millions of times throughout the pages, a considerable amount of resources could be spared this way. A theory concerning this graph puts forward the idea that the form derives from the Latin word ad,[clarification needed] using the older form of lowercase d : ∂, also used in handwritten German well into the 20th century and known to mathematicians and engineering students as the partial derivative symbol.

It has been theorized that it was originally an abbreviation of the Greek preposition ανά (transliterated ana), meaning at the rate of or per.[citation needed]

Another theory is that it derives from the Norman French "à" meaning "at" in the "each" sense, i.e. "2 widgets à £5.50 = £11.00", comes the accountancy shorthand notation in English commercial vouchers and ledgers to the 1990s, when the email usage overtook the accountancy usage. It is also used like this in Modern French, Swedish or Czech; in this view, the at-symbol is a stylised form of à, which avoids raising the writing hand from the page in drawing the symbol. The compromise between @ and à in French handwriting is found in street market signs.[citation needed]

Whatever the origin of the @ symbol, the history of its usage is more well-known: it has long been used in Spanish and Portuguese as an abbreviation of arroba, a unit of weight equivalent to 25 pounds, and derived from the Arabic expression of "the quarter" (الربع pronounced ar-rubʿ).[9] An Italian academic, Giorgio Stabile, claims to have traced the @ symbol to the 16th century, in a mercantile document sent by Florentine Francesco Lapi from Seville to Rome on May 4, 1536.[10] The document is about commerce with Pizarro, in particular the price of an @ of wine in Peru. Currently, the word arroba means both the at-symbol and a unit of weight. In Venetian, the symbol was interpreted to mean amphora (anfora), a unit of weight and volume based upon the capacity of the standard amphora jar since the 6th century.

Until now the first historical document containing a symbol resembling a @ as a commercial one is the Spanish "Taula de Ariza", a registry to denote a wheat shipment from Castile to Aragon in 1448; even though the oldest fully developed modern @ sign is the one found on the above-mentioned Florentine letter.[10]

In contemporary English usage, @ is a commercial symbol, called at site or at rate meaning at and at the rate of. It has rarely been used in financial documents[clarification needed] or grocers' price tags, and is not used in standard typography.[11]

In 2012, "@" was registered as a trademark with the German Patent and Trade Mark Office.[12] A cancellation request was filed in 2013, and the cancellation was ultimately confirmed by the German Federal Patent Court in 2017.[13]

A common contemporary use of @ is in email addresses (using the SMTP system), as in jdoe@example.com (the user jdoe located at the domain example.com). BBN Technologies' Ray Tomlinson is credited with introducing this usage in 1971.[14] This idea of the symbol representing located at in the form user@host is also seen in other tools and protocols; for example, the Unix shell command ssh jdoe@example.net tries to establish an ssh connection to the computer with the hostnameexample.net using the username jdoe.

On web pages, organizations often obscure email addresses of their members or employees by omitting the @. This practice, known as address munging, makes the email addresses less vulnerable to spam programs that scan the internet for them.

On some social media platforms and forums, usernames are in the form @johndoe; this type of username is frequently referred to as a "handle".

On online forums without threaded discussions, @ is commonly used to denote a reply; for instance: @Jane to respond to a comment Jane made earlier. Similarly, in some cases, @ is used for "attention" in email messages originally sent to someone else. For example, if an email was sent from Catherine to Steve, but in the body of the email, Catherine wants to make Keirsten aware of something, Catherine will start the line @Keirsten to indicate to Keirsten that the following sentence concerns her. This also helps with mobile email users who cannot see bold or color in email.

In microblogging (such as Twitter and GNU social-based microblogs), @ before the user name is used to send publicly readable replies (e.g. @otheruser: Message text here). The blog and client software can automatically interpret these as links to the user in question. When included as part of a person's or company's contact details, an @ symbol followed by a name is normally understood to refer to a Twitter ID. A similar use of the @ symbol was also made available to Facebook users on September 15, 2009.[15] In Internet Relay Chat (IRC), it is shown before users' nicks to denote they have operator status on a channel.

In American English the @ can be used to add information about a sporting event. Where opposing sports teams have their names separated by a "v" (for versus), the away team can be written first - and the normal "v" replaced with @ to convey at which team's home field the game will be played.[16] This usage is not followed in British English, since conventionally the home team is written first.

In C#, it denotes "verbatim strings", where no characters are escaped and two double-quote characters represent a single double-quote.[19] As a prefix it also allows keywords to be used as identifiers,[20] a form of stropping.

In D, it denotes function Atattributes: like: @safe, @nogc, user defined @('from_user') which can be evaluated at compile time (with __traits) or @property to declare properties, which are functions that can be syntactically treated as if they were fields or variables.[21]

In DIGITAL Command Language, the @ character was the command used to execute a command procedure. To run the command procedure VMSINSTAL.COM, one would type @VMSINSTAL at the command prompt.

In Forth, it is used to fetch values from the address on the top of the stack. The operator is pronounced as "fetch".

In Haskell, it is used in so-called as-patterns. This notation can be used to give aliases to patterns, making them more readable.

In Scala, it is used to denote annotations (as in Java), and also to bind names to subpatterns in pattern-matching expressions.

In Swift, @ prefixes "annotations" that can be applied to classes or members. Annotations tell the compiler to apply special semantics to the declaration like keywords, without adding keywords to the language.

In several xBase-type programming languages, like DBASE, FoxPro/Visual FoxPro and Clipper, it is used to denote position on the screen. For example: @1,1 SAY "HELLO" to show the word "HELLO" in line 1, column 1.

In a Windows Batch file, the @ symbol at the start of a line suppresses the echoing of that command. In other words, is the same as ECHO OFF applied to the current line only. Normally a Windows command is executed and takes effect from the next line onward, but @ is a rare example of a command that takes effect immediately. It is most commonly used in the form @echo off which not only switches off echoing but prevents the command line itself from being echoed.[25][26]

In Windows PowerShell, @ is used as array operator for array and hash table literals and for enclosing here-string literals.[27]

In the Domain Name System, @ is used to represent the $ORIGIN, typically the "root" of the domain without a prefixed sub-domain. (Ex: wikipedia.org vs. www.wikipedia.org)

In Portuguese and Spanish, where many words end in "-o" when in the masculine gender and end "-a" in the feminine, @ is sometimes used as a gender-neutral substitute for the default "o" ending.[28] For example, the word amigos traditionally represents not only male friends, but also a mixed group, or where the genders are not known. The proponents of gender-inclusive language would replace it with amig@s in these latter two cases, and use amigos only when the group referred to is all-male and amigas only when the group is all female. The Real Academia Española disapproves of this usage.[29]

In (especially English) scientific and technical literature, @ is used to describe the conditions under which data are valid or a measurement has been made. E.g. the density of saltwater may read d = 1.050 g/cm3 @ 15 °C (read "at" for @), density of a gas d = 0.150 g/L @ 20 °C, 1 bar, or noise of a car 81 dB @ 80 km/h (speed).

As an abbreviation for alias in articles about missing persons, obituaries, brief reports - for instance: "John Smith @ Jean Smyth" (a possible abbreviation of aka).[citation needed] For example, a Chinese Singaporean may use two transliterations of his or her Chinese name (e.g., Mao Tse-Tung @ Mao Zedong).

This section should specify the language of its non-English content, using {{lang}}, with an appropriate ISO 639 code.See why.(September 2019)

In many languages other than English, although most typewriters included the symbol, the use of @ was less common before email became widespread in the mid-1990s. Consequently, it is often perceived in those languages as denoting "the Internet", computerization, or modernization in general.

In Afrikaans, it is called aapstert, meaning "monkey tail", similarly to the Dutch use of the word (aap is the word for 'monkey' or 'ape' in Dutch, stert comes from the Dutch staart).

In Bulgarian, it is called кльомба (klyomba – "a badly written letter"), маймунско а (maymunsko a – "monkey A"), маймунка (maimunka – "little monkey"), or баница ("banitsa" - a pastry roll often made in a shape similar to the character)

In Catalan, it is called arrova ("a unit of measure") or ensaïmada (because of the similar shape of this food).

In mainland China, it used to be called 圈A (pronounced quān A), meaning "circled A / enclosed A", or 花A (pronounced huā A), meaning "lacy A", and sometimes as 小老鼠 (pronounced xiǎo lǎoshǔ), meaning "little mouse".[31] Nowadays, for most of China's youth, it is called 艾特 (pronounced ài tè), which is the phonetic transcription from "at".

In Croatian, it is most often referred to by the English word "at" (pronounced et), and less commonly and more formally, with the preposition "pri" (with the addressee in the nominative case, not locative as per usual rection of "pri"), meaning "at", "chez" or "by". Informally, it is called a manki, coming from the local pronunciation of the English word "monkey". Note that the Croatian words for monkey, majmun, opica, jopec, šimija are not used to denote the symbol, except seldom the latter words regionally.

In Danish, it is snabel-a ("elephant's trunk A"). It is not used for prices, where in Danish a alone means at (per piece).

In Dutch, it is called apenstaartje ("monkeystail"). The "a" is the first character of the Dutch word "aap" which means "monkey" or "ape", "apen" is the plural of "aap". However, the use of the English "at" has become increasingly popular in Dutch.

In Esperanto, it is called ĉe-signo ("at" – for the email use, with an address like "zamenhof@esperanto.org" pronounced zamenhof ĉe esperanto punkto org), po-signo ("each" – refers only to the mathematical use), or heliko (meaning "snail").

In Faroese, it is kurla, hjá ("at"), tranta, or snápil-a ("[elephant's] trunk A").

In Finnish, it was originally called taksamerkki ("fee sign") or yksikköhinnan merkki ("unit price sign"), but these names are long obsolete and now rarely understood. Nowadays, it is officially ät-merkki, according to the national standardization institute SFS; frequently also spelled "at-merkki". Other names include kissanhäntä ("cat's tail") and miukumauku ("miaow-meow").

In French, it is now officially the arobase[32][33] (also spelled arrobase or arrobe), or a commercial (though this is most commonly used in French-speaking Canada, and should normally only be used when quoting prices; it should always be called arobase or, better yet, arobas when in an email address). Its origin is the same as that of the Spanish word, which could be derived from the Arabicar-roub. In France, it is also common (especially for younger generations) to say the English word "at" when spelling out an email address.[citation needed] In everyday Québec French, one often hears "a commercial" when sounding out an e-mail address, while TV and radio hosts are more likely to use arobase.

In German, it has sometimes been referred to as Klammeraffe (meaning "spider monkey") or Affenschwanz (meaning "monkeystail". Klammeraffe or Affenschwanz refer to the similarity of @ to the tail of a monkey[34][better source needed] grabbing a branch. More recently, it is commonly referred to as at, as in English.

In Greek, it is most often referred to as παπάκι (papaki), meaning "duckling",[35] due to the similarity it bears with comic character designs for ducks.

In Greenlandic, and Inuit language, it is called aajusaq meaning "A-like" or "something that looks like A".

In Hebrew, it is colloquially known as שטרודל (shtrúdel), due to the visual resemblance to a cross-section cut of a strudel cake. The normative term, invented by the Academy of the Hebrew Language, is כרוכית (krukhít), which is another Hebrew word for "strudel", but is rarely used.

In Hungarian, it is called kukac (a playful synonym for "worm" or "maggot").

In Icelandic, it is referred to as atmerkið ("the at sign") or hjá, which is a direct translation of the English word "at".

In Indian English, speakers often say at the rate of (with e-mail addresses quoted as "example at the rate of example.com").

In Indonesian, it is usually et. Variations exist – especially if verbal communication is very noisy – such as a bundar and a bulat (both meaning "circled A"), a keong ("snail A"), and (most rarely) a monyet ("monkey A").

In Irish, it is ag (meaning "at") or comhartha @/ag (meaning "at sign").

In Italian, it is chiocciola ("snail") or a commerciale, sometimes at (pronounced more often [ˈɛt] and rarely [ˈat]) or ad.

In Japanese, it is called attomāku (アットマーク, from the English words "at mark"). The word is wasei-eigo, a loan word from the English language.

In Kazakh, it is officially called айқұлақ ("moon's ear"), and sometimes unofficially referred to as ит басы ("dog's head").

In Korean, it is called golbaeng-i (골뱅이, meaning "bai top shells"), a dialectal form of whelk.

In Luxembourgish it used to be called Afeschwanz ("monkey tail"), but due to widespread use, it is now called at, as in English.

In Macedonian, it is called мајмунче (my-moon-cheh – "little monkey").

In Malay, it is called alias when it is used in names and di when it is used in email addresses, "di" being the Malay word for "at". It is also commonly used to abbreviate atau which means "or" / "either".

In Morse code, it is known as a "commat", consisting of the Morse code for the "A" and "C" which run together as one character: ·--·-·. The symbol was added in 2004 for use with email addresses,[36] the only official change to Morse code since World War I.

In Nepali, the symbol is called "at the rate." Commonly, people will give their email addresses by including the phrase "at the rate".

In Norwegian, it is officially called krøllalfa ("curly alpha" or "alpha twirl"), and commonly as alfakrøll. Sometimes snabel-a, the Swedish/Danish name (which means "trunk A", as in "elephant's trunk"), is used. Commonly, people will call the symbol [æt] (as in English), particularly when giving their email addresses.

In Polish, it is officially called małpa ("monkey"). Rarely, the English word "at" is used.

In Portuguese, it is called arroba (from the Arabic arrub). The word "arroba" is also used for a weight measure in Portuguese. One arroba is equivalent to 32 old Portuguese pounds, approximately 14.7 kg, and both the weight and the symbol are called arroba. In Brazil, cattle are still priced by the arroba – now rounded to 15 kg. (This naming is because the at sign was used to represent this measure.)

In Romanian, it is most commonly called at, but also colloquially called coadă de maimuţă ("monkey tail") or a-rond. The latter is commonly used, and it comes from the word "round" (from its shape), but that is nothing like the mathematical symbol A-rond (rounded A). Others call it aron, or la (Romanian word for at).

In Spanish-speaking countries, it denotes a pre-metric unit of weight. While there are regional variations in Spain and Mexico, it is typically considered to represent approximately 25 pounds (11.5 kg), and both the weight and the symbol are called arroba.